WASHINGTON — The Trump administration views a French proposal to extend a $15 billion credit line to Iran with some scepticism, U.S. officials said on Wednesday, adding that they had not seen any concrete proposal that would be in keeping with U.S. sanctions on Tehran.

"We are pretty sceptical of this," a senior administration official told reporters during a conference call.

France has floated the idea of offering Iran about $15 billion in credit lines until the end of this year if Tehran comes fully back into compliance with its 2015 nuclear deal, according to Western and Iranian sources.

Such a move would require approval by the United States, which under U.S. President Donald Trump pulled out of the pact and has since sought to pursue a "maximum pressure" campaign against Iran.

"We have not yet seen anything, a concrete proposal that would be compliant with our sanctions and other actions so it's very difficult to judge," the U.S. official said.

Trump "is in close coordination with our partners and allies, listening to ideas, but we haven't seen anything yet that has any more prospects of becoming real than any of the other schemes that have been floated over the last year," the official added.

Asked about the U.S. response to France's proposal, a spokeswoman for the French Foreign Ministry said: "Many things still need to be resolved."